Billiard Balls in a Mould

[Turbo_Sheep4]

Hi can someone help me answer this question which i have been stuck on for a long while now.

10. The diagram shows the balls on a billiard table put together using a plastic mould in the form of a triangle with arched vertices. The diameter of each ball is 5.7cm. The height of the mould is equal to that of each ball.

a) Calculate the volume of empty space in between the balls as a percentage of the total volume of the plastic mould.

b) Find the perimeter of the plastic mould.

Thanks in advance

 

[ksdhart2]

Well, if you say you've been "stuck on [this] for a long while now, " meaning you should have plenty of attempts. Please share some of them, even if you know they're wrong. That way, we won't give you advice doing something you've already done. Thank you.

As an additional hint, you might also read this thread from 2009, which features a similar problem to yours.